Given the importance of protease’s worldwide market, the determination of optimum conditions and the development of a standard protocol are critical during selection of a reliable method to determine its bioactivity. This paper uses quality control theory to validate a modified version of a method proposed by Charney and Tomarelli in 1947. The results obtained showed that using azocasein substrate bromelain had its optimum at 45°C and pH 9 (Glycine-NaOH 100 mM). We also quantified the limit of detection (LoD) and limit of quantification (LoQ) in the above-mentioned optimum (0.072 and 0.494 mg·mL⁻¹of azocasein, resp.) and a calibration curve that correlates optical density with the amount of substrate digested. In all analysed samples, we observed a significant decrease in response after storage (around 17%), which suggests its use must be immediately after preparation. Thus, the protocol presented in this paper offers a significant improvement, given that subjective definitions are commonly used in the literature and this simple mathematical approach makes it clear and concise.

The essential oil of key lime (Citrus aurantifolia) was obtained by steam distillation at normal conditions (1.0 bar/25ºC) with steam at 110ºC, during 10h. The GC analysis identified about 10 main substances, being limonene, p-cymene, myrcene and beta-bisabolene the most significant compounds. Aldehyde content increased significantly during distillation time (upper phase). After 10h of process, oil has presented more than 3% of aldehydes content due to oxidative reactions.

This study focused on verifying whether the emission of air pollutants in São Paulo increases the costs and number of hospitalizations for respiratory diseases in Brazil. Data on pollutant emissions, hospitalizations, and hospital costs were collected from 2008 to 2017 and correlated with air quality standards. The results showed that the concentration of particulate matter increased each year during the study period and was highly correlated with hospitalizations due to respiratory diseases. Ozone (O₃) was within the quality standard throughout the study period but registered an increase in the mean and a positive correlation with hospitalizations due to respiratory diseases. The carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂) levels were within the quality standards throughout the study period with a decrease in the last years studied, but showed a positive correlation with hospitalizations due to respiratory diseases. The pollutant emissions and hospitalizations due to respiratory diseases had an inverse relationship with the monthly rainfall curve for São Paulo, which indicates that rainfall tended to reduce pollutant emissions and consequently hospitalizations due to inhalation of these pollutants. Because costs are directly associated with hospitalizations, both increased during the study period—302,000 hospitalizations at an average cost of 368 USD resulted in a total cost of 111 million USD. To reduce these costs, Brazil should implement stricter policies to improve the air quality of its major cities and develop a viable alternative to diesel vehicles.

Bromelain, a set of proteolytic enzymes potential pharmaceutical applications, was encapsulated in chitosan nanoparticles to enhance enzyme stability, and the effect of different chitosan sources was evaluated. Chitosan types (i.e., low molecular weight chitosan, chitosan oligosaccharide lactate, and chitosan from shrimp shells) produced nanoparticles with different physicochemical properties, however in all cases, particle size and zeta potential decreased, and polydispersity index increased after bromelain addition. Bromelain encapsulation was higher than 84% and 79% for protein content and enzymatic activity, respectively, with low molecular weight chitosan presenting the highest encapsulation efficiency. Nanoparticle suspension was also tested for accelerated stability and rheological behavior. For the chitosan–bromelain nanoparticles, an instability index below 0.3 was recorded and, in general, the loading of bromelain in chitosan nanoparticles decreased the cohesiveness of the final suspension.

Microalgae are aquatic unicellular microorganisms that can be found both in freshwater and marine systems; are capable of photosynthesis; and can grow as individual cells or associated in chains or small colonies. Microalgae cultivation has gained large momentum among researchers in the past decades due to their ability to produce value metabolites, remarkable photosynthetic efficiency, and versatile nature. The wide technological potential, and thus increasing amount of scattered knowledge, may become the very first barrier that a post graduating student, or any non-specialist reader, will face when introduced to the subject. In this review paper, we access the core aspects of microalgae technology, covering their main characteristics, and comprehensively presenting the main features of their various cultivation modes and biological activity from metabolites.

Renewable energies are cleaner forms of energy, and their use, has intensified in recent decades. Thus, this work presents a proposal for reducing the emissions, fuel cost, and respiratory disease hospitalizations using environmental cost accounting principles to produce biodiesel production from waste frying oil. In our methodology, we conducted surveys, and collected waste cooking oil samples from local households and restaurants in São Paulo city, Brazil. Then, we produced biodiesel using these samples. Data on air pollutants were collected and correlated with the number of hospitalizations for respiratory diseases and their costs. Our results indicate that 330,000 respiratory disease hospitalizations were recorded in São Paulo city between 2009 and 2018, and the total cost for the Brazilian government reached US $117 million. Improving the city air quality by switching from fossil fuels to biodiesel could reduce the annual number of hospitalizations to 9880 and cost US $3.518 million, because the amount of pollutants emitted from burning fossil fuels was positively correlated with the number of respiratory disease hospitalizations and their costs. Moreover, the emission rates of particulate matter with particles less than 10 and 2.5 µm in diameter exceeded the World Health Organization limits throughout the study period. Using the survey data, we estimated that the average monthly quantity of waste cooking oil was 9794.6 m³, which could generate 9191.2 m³ of biodiesel and produce 239,713 t CO₂ of carbon credits. Environmental cost accounting revealed that it would be possible to achieve an annual profit of approximately US $300 million from the sale of excess biodiesel, carbon credits, and glycerine, and fuel acquisition savings which could improve the image of São Paulo city and quality of life of its residents. Thus, we present this as a way to reduce cost and hospitalizations, and increase the number of available hospital beds for other diseases, such as COVID-19.